Facial paralysis has many causes including tumors, trauma, prior surgery, infection, and inflammatory conditions.
A cause for facial paralysis is sometimes not found and this is referred to as Bell’s palsy. A Bell’s palsy is a temporary or permanent weakness or paralysis of the facial nerve.
Facial weakness or paralysis can affect patients in various ways. The facial nerve has branches that connect to the facial muscles and they direct the muscles to act. These muscles allow you to raise your eyebrows, close your eyes, smile, purse your lips, and contribute to additional functions of the mouth such as speaking, eating, and drinking. The muscles of the eyelid help protect the eye and to also push tears into the tear drain.
A patient with facial paralysis may have difficulty raising the eyebrow, so the heavy weight would push down on the upper lid and obstruct the patient’s field of vision.
There can also be difficulty closing the eye, so the eye would stay open and become dry, which can be extremely painful and have long-term consequences if not addressed.
The lower eyelid can weaken, which would also contribute to dry eye. Tearing can occur because the tears are not being pushed toward the tear drain due to a weak blink mechanism, as well as reflex tearing from dry eye.
The corner of the mouth can become droopy, resulting in an asymmetric expression and difficulty with eating, drinking, and speech.
Face – Dynamic slings
Dynamic slings allow the patient to activate the weakened area of the face. Another muscle that is functioning appropriately (or better) is connected to the facial structure that is weak. The weakened facial structure therefore now relies on a new muscle to achieve its intended function. One example of this is a temporal tendon transfer as a temporalis sling.
Face – Temporalis Tendon Transfer- A dynamic sling
The temporalis muscle and tendon span across the side of the head, across the temple, and insert onto the jawbone.
Although this muscle is indeed involved in movement of the face, specifically the jaw, it is not controlled by the facial nerve. Rather, it is innervated by the trigeminal nerve. This muscle is therefore not directly affected in facial nerve paralysis.
This procedure therefore involves utilizing this muscle. It involves the transfer of this muscle and tendon to the corner of the mouth. The patient then learns to activate the muscle in order to move the corner of the mouth.
Eyelid - Gold or Platinum Weights
A gold or platinum weight can be placed in the upper eyelid if there is lagophthalmos, or an inability to close the eye. This adds weight to the eyelid and assists in closing the eyelid and therefore protecting the eye. The actual weight of the implant must be carefully considered as too much weight would obstruct vision and too little weight would not provide enough protection. This weight should also be placed in a very specific location in order to minimize the risk of implant exposure, extrusion, and/or infection, to reduce visibility of the scar incision and the weight itself, and in a manner that can also optimize the function of the muscle that lifts the eyelid. The appropriate function of this muscle is needed because the eyelid has been lowered by the weight and the patient will want to be able to open the eye naturally to see.
Eyelid - Facial Fillers
Filler can be placed in various planes of the upper eyelid to add weight and/or to also interfere with the function of the muscle that lifts the eyelid. With this help, closing and blinking can improve. This is sometimes used as a temporizing technique or when surgery cannot be performed.
Eyelid - Lower eyelid surgery
In lower eyelid facial paralysis surgery, the lower eyelid is tightened through various procedures.
Some of these include tightening the lower eyelid with sutures only, harvesting a fascia lata thigh graft and utilizing it as a sling for the lower eyelid, and/or performing a mycotaneous flap or midface lift for support.
Face and Eyelid – Myocutaneous flap or Midface lift
The lower eyelid may be weak, paralyzed, and/or turned out as a result of facial paralysis. This will cause the eye to be exposed and dry. This can also have an effect on how the tears empty through the tear drain. The blinking mechanism helps push the tears toward the tear drain. In eyelid paralysis, the tears instead collect and then spill over, causing tearing. This can interfere with vision and can also be cumbersome.
A myocutaneous flap or midface lift can be performed in conjunction with eyelid surgery to help support the lower eyelid. It can also be performed to improve facial symmetry, another emotional and psychological concern of facial paralysis patients.
Face and Eyelid – Static slings
Static slings are support techniques that do not change with movement of the facial muscles. In other words, the effect is seen in repose. One way to perform this is by using sutures such as Goretex or harvested tissue such as a fascia lata graft.